Question

How many ions are present in 30.0mL of 0.600M Na2CO3 solution

Answer 1

Molarity = moles / volume in dm3 or litre

1st of all convert volume 30 mL into Litre or dm3 by dividing it with 1000. then it becomes 30/1000 = 0.03

Now find the moles by arranging the above equation, i.e
moles = molarity * volume
moles = 0.6 * 0.03
moles = 0.018

now we have got the moles of Na2CO3

1 mole of Na2CO3 = 3 moles of total ions. (2NA+ and CO-2)
0.018 moles of Na2CO3 = 3*0.018
0.018 moles of Na2CO3 = 0.054 moles of ions

now apply the formula, i.e number of atoms or ions = moles * Na (avogadros number.)

number of ions = moles of ions * Na (avogadro's number)
number of ions = 0.054 * 6.022 * 10^{3}
number of ions = 3.025 * 10^{22}

Answer 2

good work, but next time dont solve it. Just tell them the steps they need to take.

Answer 3

ok and thanks